Python functools partialmethod() Function

The Pythonpartialmethod() function is similar to the partial function. The main difference is partialmethod() is used within the class method.

The function allows us to create a new function with a specific number of arguments predefined from another function. A partial() function is used to specify a function by reducing the number of parameters it requires.

Syntax

Following is the syntax for thepartialmethod() function.

functools.partialmethod(func, /, *args, **keywords)

Parameters

The parameters for thepartialmethod() function are listed below −

• / : This indicates that all parameters must be specified positionally.
• *args : This is the positional argument used to set in advance for the new function.
• **keywords : This is the keyword argument used to predefined the new function.

Return Value

This function returns a new partial method descriptor.

Example 1

In the below example, we double the given values by multiplying the predefined values using thepartialmethod() function.

import functoolsclass Calculator:    def multiply(x, y, z):       return y*z    double = functools.partialmethod(multiply, 4)a = Calculator()print(a.double(10))print(a.double(20))

Output

The result is generated as follows −

4080

Example 2

This code defines the Adder class with an add method that sums three numbers using thepartialmethod() function. The add_ten method pre fills the first argument with 10, with the remaining arguments provided during the method call.

import functoolsclass Adder:    def add(self, x, y, z):        return x + y + z    add_ten = functools.partialmethod(add, 10)adder = Adder()print(adder.add_ten(10, 20))  print(adder.add_ten(15, 25))

Output

The code is generated as follows −

4050

Example 3

Here, we are defining the power class with power method that rises a base to an exponent. When square is called usingpartialmethod() function then it returns the square of the given number.

import functoolsclass Power:  def power(self, base, exponent):    return base**exponent  square = functools.partialmethod(power, exponent = 4)power = Power()print(power.square(16))print(power.square(8))

Output

The output is obtained as follows −

655364096